1. Field
The present disclosure relates generally to drains and in particular to mechanical drains. More particularly, the present application is directed to a method and apparatus for drain valves composed of shape memory alloys.
2. Background
Pods, enclosures, and various structures during their service life collect large amounts of moisture or water inside the enclosure, structure, or pods. The water is collected by condensation from atmospheric conditions, operating environmental control systems, and other avionics and electrical equipment. This collecting water may create corrosion issues that may damage the underlying structure and other components.
Currently, moisture and fluids may be drained from enclosures using open drain holes. In cases where the enclosure producing the moisture is sealed, drain holes may not be practical.
Mechanical drains may also be used. The mechanical drains are opened and closed manually by a technician or other personnel. However, it may not be possible to eliminate or drain the water by a technician using a mechanical drain when the aircraft, cargo hauler, or other apparatus is in operation or when it is difficult or impossible to reach the mechanical drain.
Existing solutions are open and/or mechanically plugged drain holes in a structure. In some aircraft, open drain holes are provided on the lower skin of the avionics bays. These small drain holes are used to drain the water from the bay. However, large amounts of water can sometimes collect at times as the humidity increases, significant accumulation occurs potentially making it difficult to eliminate water from the bay.
The open holes may become clogged with dirt, mud, and other foreign objects that can block the drain hole and prevent draining of the enclosed bay. In addition, open holes sometimes require wire mesh to be placed over the open holes in areas where avionics equipment is installed to prevent electromagnetic buildup. However, the wire mesh can permit dirt, mud, and other foreign objects to clog the wire holes or openings and further prevent draining of the enclosed bay.
In addition, some aircraft are capable of landing in water, but in order to accomplish a water landing with the aircraft, drain plugs must be installed in all the drain holes before a water landing can be made. The installation of the plugs takes approximately 1.5 hours for a single crewmember or 25 minutes for 3 crewmembers. Although the fuselage is somewhat sealed, water may still collect in the bilge area. There may be no way to remove the standing water in the bilge area until after the aircraft lands at an airport or other maintenance facility.
In addition, currently available valves that are electrically operated using magnetic switches and other solenoid operated valves are heavy and need to be sealed for use in a high moisture environment.